Take a look at this soldered joint I melted off. Literally holding by a solder thread and all joints seem same. Some of the pipes are also cut at a bad angle, obviously with a hacksaw, (this one in photo is done badly with a pipe cutter) Pipes half in, barely soldered. This is original work (30 years old) on a system now converted to combi high pressure in a flat.
Really shocking "plumbers" could do such consistently useless soldering.
View attachment 26251
Note the fitting shows bare copper never soldered also. I am removing every fitting above the floor, but it is a worrying thought that the pipes are buried in screed floors. Not a good idea to even move the pipes